Yeah, if you don't like the hose fitting and can't stop it leaking, use those new found plumbing skills to replace it with what you think is good. With an aluminum tank and no need for an anode rod, you could replace it with some fittings and a valve. You might also replace it with a "Hotrod kit" so you have an electric element. Lots of ways to deal with the water heater drain.
One thing I'd suggest to do before you try firing it is to take apart the burner, the pilot, the thermocouple (if fitted with one), and both orifices, the pilot and the main burner, and clean it all up like a shiny penny. The orifices you can clean with a solvent or a heavy cleaning soap. Just soak them and blow out with compressed air. This is what I did with my older heater and it works fine.
You may be able to find some other building tips in the restoration thread in my signature line,
The Cowboy/Hilton. I'm a guy like you, picking up the pieces and putting them to work. Need any trailer windows? :B